McIntyre, a mining consultant with no climatology experience, says the famous hockey stick graph of the last couple of thousands years of global temperatures, is based on faulty tree-ring proxy data, and that if you use a slightly different data set, global warming disappears. Here’s his latest graph:

The red line is a version of the temperature record that has been independently verified multiple times by actual climatologists. The black line is the product of McIntyre’s selection of tree cores. You will notice it differs from the red line only for the last century or so. He says this means the Earth is not warming.

But we don’t need proxy data from tree rings or any other source to know what the temperatures have been for the last century because we have actual temperature measurements, measurements that are in accord with the red line. Therefore, there’s something wrong with the data McIntyre has chosen.

Comments

1: MBH was the “famous” Hockey Stick and was 600 then 1,000 years, not 2,000. I’m not sure if you’re confusing that with the Yamal series which was published after.
2: In the graph you show, the red line depicts the Yamal series as archived, not the CRU surface temp recon.
3: The black line isn’t originally the selection of McIntyre but of Briffa’s coauthor Schweingruber

That’s a great paraphrase. The Yamal set of tree rings aren’t accurately reflecting temperatures now, so we lose confidence in their ability to reflect past temperatures….am I correct?

Perhaps if McIntyre and Watts got together it would all work out. Watts shows that the land-based observations are faulty, McIntyre finds some tree rings that show there is no warming. Oops, I hope I’m not giving anyone ideas.

The proxy with the Yamal data doesn’t show the hockeystick, and yet you claim that the hockey stick is real. That means the proxies do not show the correct temperatures. You have no information from the proxies in the past that shows what is normal and what isn’t normal.

You can’t conclude that the current temperatures are abnormal based on the evidence, because the evidence from the proxies does not agree with the known temperature record.

Can we trust the rest of your reporting if you can’t work out the consequences?

To know how to interpret proxy data from the distant past, first you have to calibrate how you interpret them. You do this by comparing them to actual measurements. In this case, we need to compare tree-ring core data from the modern era with temperature data from the modern era. Then you can figure out what the distant (pre-thermometer era) proxy data really mean.

If the proxy data you are using don’t match the modern measurements, something is wrong with the way you’re interpreting the proxy data. Period.

A serious problem with the original MBH hockey stick was the overweighting of the Graybill bristlecone tree ring series, which showed neither the Medieval Warm Period nor the Little Ice Age, but did show increased growth recently. The much larger and more recent Ababneh series failed to show any hockey stick.

This produced an overweighting of the one tree, YAD061. McIntyre replaced the ten trees with the Schweingruber data, and inverted the hockey stick. Reincluding the ten with the new data does not restore the upswing.

My conclusion is that these tree rings are simply not a good proxy for temperature.

Oh, and Mike McMillan, just ’cause McI says something is true, does not mean it’s true. You’ve done a nice recap of McI’s false claims, but they’re still false.

Nick:

The proxy with the Yamal data doesn’t show the hockeystick, and yet you claim that the hockey stick is real.

Uh, yes, Briffa’s Yamal reconstruction does show the hockeystick, which is McI’s complaint.

McI leaves those out and tosses in various other chronologies which were rejected by Briffa because analysis shows them to be poor temperature proxies (and this analysis used to choose chronologies is NOT based on matching or not matching the instrumental record, but rather on totally different selection criteria).

McI gives no rationale for his arbitrary shoving in of series he likes versus series he doesn’t like.

Nothing, nada, zippo from Jimboy or from NASA when their ice melt go-to guy Marco Tedesco reports that Antarctica has set a record for the lack of surface ice melt – even more interestingly coming on the heels of a near-record low ice-melt year last summer. What gives? If ice melt is an important enough topic to warrant regular updates of the goings-on across Greenland, it is not important enough to elucidate the history and recent behavior across Antarctica? Typical. crickets chirping…..

“If the proxy data you are using don’t match the modern measurements, something is wrong with the way you’re interpreting the proxy data. Period.”

Alternatively, the things that you think are proxies (polar tree rings) for something else(temperature), aren’t. That is the crux of McIntyre’s argument.

He is not saying that Earth isn’t warming, just that there is good reason to believe that the tree ring data used by many climate scientists to assert how exceptionally warm our current climate is, don’t actually tell us anything much about temperature’s present or past. Quite simple really

Mence Kehlen: I have a meassage caught in moderation because there are too many links, but here’s the short version:

This isn’t making the news because it isn’t news — it’s something that these scientists have been watching and working on understanding for two decades now. What YOU’RE not seeing is that this is part of a complex picture, where increasing precipitation and freeze is happening in some areas of the east and surrounding sea, but there is drastic thinning of ice sheets and loss of mass is happening in the west and the western ice shelves even when there is little surface melt. Overall, the picture is still one of climate change, where global warming has complex regional effects.

The scientists who work on this issue have more of the picture than you do; it isn’t malice on their part, “hiding” something from the public, it is ignorance on your part of what is going on and how it fits together, and what the relevant parts of the picture are.

Negative melting anomalies observed in recent years do not contradict recently published results on surface temperature trends over Antarctica [e.g., Steig et al., 2009]. The time period used for those studies extends back to the 1950’s, well beyond 1980, and the largest temperature increases are found during winter and spring rather than summer, and are generally limited to West Antarctica and the Antarctic Peninsula. Summer SAM trends have increased since the 1970s [Marshall, 2003], suppressing warming over much of Antarctica during the satellite melt record [Turner et al., 2005]. Moreover, melting and surface temperature are not necessarily linearly related because the entire surface energy balance must be considered [Liston and Winther, 2005; Torinesi et al., 2003].

pablo: In the original graphs in Briffa’s paper, that y-axis represented the “mean June–July temperature anomalies relative to mean of the full reconstructed series”, in degrees C, with the “full reconstructed series” being used as the baseline drawn from many more locations over 2,000 years. I assume it still means something like that, though I could be wrong.

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